var verify_discount_amount_notnull_baseMsg = JSON.parse('{"CODE":0, "ACTION":"","LEVEL":"T1", "MSG":"","DATA":"","SCRIPTNAME":"verify_discount_amount_notnull"}');

if (active_discount == 1 && isNull(discount_amount)) {
    verify_discount_amount_notnull_baseMsg.CODE = 2;
    verify_discount_amount_notnull_baseMsg.ACTION = 'error';
    verify_discount_amount_notnull_baseMsg.MSG = '有补差 补差金额不能为空';
}

JSON.stringify(verify_discount_amount_notnull_baseMsg);